Coupling arrangement for dialysis
Dialysis treatment of patients has till now generally been performed at hospitals which -are partly in possession of the necessary equipment and are partly in a position to carry out the treatment in a manner such that infections * are avoided. It is highly desirable, however, that in certain cases the patients might be allowed to perform the dialysis in their- own homes, but this has encountered the difficulty that it has not been possible to provide adequate protection against the danger of infections in connection with the treatment, and the object of the invention present is to provide, a coupling arrangement for dialysis which eliminates this danger of infections so that the treatment may be left to the patients.
A catheter is implanted in the patients, the end of which extends from the body, and the catheter end must therefore be closed when the treatment is interrupted and be coupled to the dialysis device during the treatment. The coupling arrangement consists of a primary coupling means arranged to be permanently connected to the protruding end of the catheter and arranged as a bayonet coupling for a secondary coupling means, and according to the invention it is• characterized in that the primary coupling means consists of or has a surface layer,of a material, such as silver, which has an oligodynamic activity, said primary coupling means having a freely outwardly extending cone for non- self-locking cooperation with a corresponding cone face inside the bayonet cover and the secondary coupling means, respectively, said bayonet coupling between the primary coupling means and the bayonet cover, and the secondary coupling means, respectively, being constructed so that the bayonet cover and the secondary coupling means, re-
• spectively, engage the exterior of the entire primary coupling means. Such a coupling arrangement is partly based on the finding that certain heavy metals and particularly silver have been found to have an oligodynamic activity which is adequate to ensure that no live bacteria can penetrate into the catheter, and the construction of the coupling device ensures that the outwardly facing surfaces of the primary coupling means can be cleaned very easily so that there are no risks involved in leaving it to the patient to carry out said easy cleaning himself. The bayonet cover as well as the secondary coupling means may be made of a relatively cheap plastics material so that these parts may be disposed of after each application, and for each dialysis a new secondary coupling means is used then and after the dialysis a new bayonet cover, it being possible to have said parts stored sterilized so that these parts will not involve any risks of infection either.
The invention will be described more fully below with reference to the drawing, in which
figs. 1 and 2 show a primary coupling means, seen from the side" and.the end, respectively,
figs. 3 and 4 show a secondary coupling means, in axial section and seen from the end, respectively, and
figs. 5 and 6 show a secondary coupling means, in partial section and seen from the end, respectively.
Figs. 1 -and 2 show a primary coupling means consisting of a tubular connection 1 for an end of a catheter and with a coupling head 2 which has a projecting flange 3 with flat, cut faces 4 and circular grooves 5. The head 2 has also a frusto-conical projection 6 whose apex angle is expediently of the order of 60°.
OMPI IPO A bayonet cover 11 is shown in figs. 3 and 4, consisting of a cylindrical portion 12 which has a recess 13 defined by plane-parallel sides to receive the coupling he*ad 3 of the primary coupling means, the plane sides 14 of the recess mating with the cut faces 4 on the coupling head 2. Inside the bayonet cover there are grooves 15 corresponding to the grooves 5 on the primary coupling head and serving to receive parts thereof projecting at the grooves and thus to interlock the bayonet cover and the primary coupling member. Inside the bayonet cover there is also a frusto— conical recess 16 corresponding to the frusto-conic'al projection 6 of the primary coupling head.
Figs. 5 and 6 show a secondary coupling means 21 which is essentially constructed in the same manner as the bayonet cover shown in figs. 3 and 4, it having likewise internally a frusto-conical recess 26 here communicating with the interior of a tubular connection 27 which is to serve as connection for the means with a dialysis device.
While the bayonet cover and the secondary coupling means' shown in figs. 3, 4, 5 and 6 are usually made of an appropriate plastics material, the primary coupling means shown in figs. 1 and 2 is made of a material which has an oligodynamic activity, preferably silver, or it may be made of another mechanically stable material and be completely covered by a layer of silver of a suitable thickness.
OMPI